Tonometric blood pressure measurement is a non-invasive means for continuously monitoring blood pressure (BP) and obtaining additional cardiovascular parameters such as arterial stiffness, cardiac output and stroke volume. Before making such measurement, an accurate position of an artery location is required to be identified over a person's skin.
It is possible to use a single pressure sensor to search for the artery location when the sensor presses on the skin, as in U.S. Pat. No. 8,597,195. During the search, a constant hold-down pressure exerted by the sensor on the skin is required to be maintained. Due to the curvature of a body part under measurement, such as a wrist of a person, the sensor is required to finely and dynamically adjust its position to keep a constant hold-down pressure during the search. A long search time is usually resulted. U.S. Pat. No. 7,771,361 and US20100286538 suggest using an array of optical and pressure sensors to press on the skin to thereby identify the artery location. Although the search time is shorter, accuracy of the artery location is limited by the sensor dimension. High accuracy is achievable only with a small sensor size, the implementation of which is costly.
There is a need in the art for rapid and accurate identification of the artery location without a need to reduce the sensor dimension.